In order to be able to study hard objects such as metals, synthetics, fiber materials, multicomponent materials, cortex and bone substances, essentially free from artifacts, use is often made of the techniques of cross-cutting, microtome processing, or surface grinding followed by polishing. For these preparation methods, the embedding of the specimens in casting-resin block mounting media is required. In such methods, the hardness of the mounting media must be coordinated with the hardness of the given specimen. Such a coordination, however, is frequently only roughly achievable approximately, for instance because for a required slice-thickness, or when polishing, a selected average hardness of the overall specimen surface must be made.
The techniques heretofore applied in such preparations, which are dependent overall on the most extensive possible optimal coordination of the hardness of the block mounting-medium to the specimen hardness, have proven to this extent to be inadequate and in need of improvement. This is especially true for incident illumination as it requires the most extensively smooth, roughness-free specimen surfaces possible. Surface qualities of the required type are to be achieved with the use of known techniques of preparation, although generally involving time and money in further treatment. These techniques fail to a great extent, however, in multiphase systems, wherein strong hardness-differences occur in the specimen surface. Such an example can be only inadequately resolved with known preparation methods. Specifically, the soft pulp of a tooth, which is surrounded by the harder tooth enamel is such an example. Roughness-free cutting surfaces cannot be achieved. Instead, crushing and deformation occur in the specimen areas which exhibit only slight hardness. On polishing, pores and cavities present in the material are clogged with polishing compound. Test pieces prepared in such a manner are only conditionally suitable for incident illumination studies.